Barack Obama’s choice of a prominent evangelical minister to perform the invocation at his inauguration is a conciliatory gesture toward social conservatives who opposed him in November, but it is drawing fierce challenges from a gay rights movement that – in the wake of a gay marriage ban in California – is looking for a fight.

Rick Warren, the senior pastor of Saddleback Church in southern California, opposes abortion rights but has taken more liberal stances on the government role in fighting poverty, and backed away from other evangelicals’ staunch support for economic conservatism. But it’s his support for the California constitutional amendment to ban same-sex marriage that drew the most heated criticism from Democrats Wednesday.

“Your invitation to Reverend Rick Warren to deliver the invocation at your inauguration is a genuine blow to LGBT Americans,” the president of Human Rights Campaign, Joe Solomonese, wrote Obama Wednesday. “[W]e feel a deep level of disrespect when one of architects and promoters of an anti-gay agenda is given the prominence and the pulpit of your historic nomination.”

The rapid, angry reaction from a range of gay activists comes as the gay rights movement looks for an opportunity to flex its political muscle. Last summer gay groups complained, but were rebuffed by Obama, when an “ex-gay” singer led Obama’s rallies in South Carolina. And many were shocked last month when voters approved the California ban.

“There is a lot of energy and there’s a lot of anger and I think people are wanting to direct it somewhere,” Solomonese told Politico.

The selection of Warren to preside at the inauguration is not a surprise move, but it is a mirror image of President Bill Clinton’s early struggles with issues of gay rights. Obama has worked, and at times succeeded, to bridge the gap between Democrats and evangelical Christians, who form a solid section of the Republican base.

Obama opposes same-sex marriage, but also opposed the California constitutional amendment Warren backed. In selecting Warren, he is choosing to reach out to conservatives on a hot-button social issue, at the cost of antagonizing gay voters who overwhelmingly supported him.

Clinton, by contrast, drew early praise from gay rights activists by pressing to allow openly gay soldiers to serve, only to retreat into the “don’t ask, don’t tell” compromise that pleased few.

The reaction Wednesday in gay rights circles was universally negative.

“It’s a huge mistake,” said California gay rights activist Rick Jacobs, who chairs the state’s Courage Campaign. “He’s really the wrong person to lead the president into office.

“Can you imagine if he had a man of God doing the invocation who had deliberately said that Jews are not going to be saved and therefore should be excluded from what’s going on in America? People would be up in arms,” he said.

The editor of the Washington Blade, Kevin Naff, called the choice “Obama’s first big mistake.”

“His presence on the inauguration stand is a slap in the faces of the millions of GLBT voters who so enthusiastically supported him,” Naff wrote, referring to gay, lesbian, bisexual and transgendered people. “This tone-deafness to our concerns must not be tolerated. We have just endured eight years of endless assaults on our dignity and equality from a president beholden to bigoted conservative Christians. The election was supposed to have ended that era. It appears otherwise.”

Other liberal groups chimed in.

“Rick Warren gets plenty of attention through his books and media appearances. He doesn’t need or deserve this position of honor,” said the president of People for the American Way, Kathryn Kolbert, who described Warren as “someone who has in recent weeks actively promoted legalized discrimination and denigrated the lives and relationships of millions of Americans.”

Warren’s spokeswoman did not respond to a message seeking comment, but he has tried to blend personal tolerance with doctrinal disapproval of homosexuality.

“I have many gay friends, I’ve eaten dinner in gay homes. No church has probably done more for people with AIDS than Saddleback Church,” he said in a recent interview with BeliefNet.

In the same interview, he compared the “redefiniton of a marrige” to include gay marriage to legitimizing incest, child abuse, and polygamy.

Obama’s move may deepen some apparent distance between him among gays and lesbians, one of the very few core Democratic groups among whom his performance was worse than John Kerry’s in 2004. Exit polls suggested that John McCain won 27% of the gay vote in November, up four points from Bush’s 2004 tally – even as almost all other voters slid toward Obama.

But despite the symbolism of picking Warren, Obama is likely to shift several substantive policy areas in directions that will please gay voters and their political leaders, including a pledge to end “don’t ask, don’t tell” in military service.

And some gay activists were holding out hope that they would either persuade Obama to dump Warren or Warren to change his mind.

“Rick Warren did a real disservice to gay families in California and across the country by casually supporting our continued exclusion from marriage,” said the founder of the pro-same sex marriage Freedom to Marry, Evan Wolfson. “I hope in the spirit of the new era that’s dawning, he will open his heart and speak to all Americans about inclusion and our country’s commitment to equality.”